A stored-spring-energy type actuator mechanism of the above kind is described, for example, in "Sprecher Energie Revue" No. 1/86 on pages 4 and 5. In this arrangement energy for switching on a high-voltage circuit breaker and for simultaneously loading a circuit-breaker switch-off spring is stored in a spring-energy accumulator. The spring-energy accumulator can be loaded by means of an electric motor or by hand. When the high-voltage circuit breaker is switched on and the spring-energy accumulator and the switch-off spring accumulator are loaded, the circuit breaker can subsequently be switched off, switched on and switched off again without the spring-energy accumulator having to be recharged. For reasons of reliability of supply, it is desirable that the circuit breaker be able to execute a plurality of such switching actions even in the event of failure of the feed network of the actuator mechanism. In order to provide such operation, it has been proposed, for example, in German Offenlegungsschrift No. 3,540,674, to make the stored energy of the spring-energy accumulator sufficiently high that the high-voltage circuit breaker can be switched on several times and the switch-off spring accumulator charged at the same time. As a result of the spring characteristics, however, if the spring-energy accumulator is not re-charged, there is substantially more energy available for the first switching action than for subsequent switching actions.
This requires on the one hand additional damping elements for dissipating excess energy and on the other hand appropriate dimensioning of the actuator mechanism for substantial stored energies and the high forces consequently occurring.